libxnvctrl (NVIDIA NV-CONTROL X extension)

The NV-CONTROL X extension provides a mechanism for X clients to query
and set configuration parameters of the NVIDIA X driver. State set by the
NV-CONTROL X extension is assumed to be persistent only for the current
server generation. This can be useful for programs such as conky,
mate-sensors-applet, and xfce4-sensors-plugin to allow for realtime
monitoring of your NVIDIA cards temperature, fan speed, memory, etc.
